Soraka's E need to quality of life change
Her E doesnt trigger the silence fast enough while targets are inside the circle. So if a untargetable champion has her E under them and their untargetable finishes between ticks of silence they can cast enough ability to get out. If you can react fast enough you can avoid being silenced altogether with some abilities while standing in her E. Which was not intended
Its basically impossible to catch vlad and fizz because their W and E's allow them to always get out of my silence after zhonyas every time because the silence doesnt tick fast enough.
By making her E have its silence tick faster it can make her silence a lot more reliable. It wouldnt break her, just make her kit work as intended.
Equinox,
Void Ooze, or
Cannon Barrage a moment before becoming targetable again. It shouldn't matter too much for balance purposes, since the only ability of this type that isn't a slow or DoT (or both) is Soraka's E.